Many digital image formats include meta-data which records aspects of an image that are in addition to the raw digital image pixel data Examples of such attributes include a copyright notice, type of capture device, flash usage, type of lens, date of capture, programs the image has been edited with, regions of interest, and more. In many image formats there are both well known meta-data items which, because of their standard-mandated identifiers and format, can be programmatically processed, as well as application specific meta-data items. These application specific meta-data items may be related to only one or a few programs or may be end-user invented and thus not programmatically interpretable by any particular application.
There exist many computer application programs which combine digital images in various ways, or transform a single image. Examples include image editors such as Adobe PhotoShop. Other examples include panorama stitching applications that combine two or more partially overlapping images of the same scene into a single larger digital image. When these applications produce a new digital image from one or more original digital images they must make decisions on what meta-data from the original image(s) is passed to the new image, what meta-data is discarded, or modified in some way. Typically, meta-data copying actions may be taken on specific metadata elements, which have well known characteristics. For example, a program may preserve all copyright notices from all source images in the composite image because the characteristics of copyright notices are known to the application designer. However, these applications suffer from the disadvantage of being inflexible in that they are limited to specific well known meta data elements.